Press apparatus

ABSTRACT

Blanking apparatus for highly accurate blanking operations and the like having a punch holder supporting a punch movable toward and away from a workpiece and such punch holder carrying with it, during a portion of its movement, a pressure applying member which exerts a strong compressive or restraining force on the workpiece during the interval that the punch is piercing the workpiece. During a portion of punch holder movement, pressure applying member movement therewith is arrested whereby relative movement between the pressure applying member and the punch holder occurs. The present invention provides novel means which prevents cocking or tilting the pressure applying member during relative movement between the latter and the punch holder.

United States Patent [72] in r Robert 50min 2,230,802 2/l94l Klein 83/458 warren Ohm Primary Examiner-William S. Lawson [2]] Appl. No. 838,866 A" d K k 22 Filed July 3,1969 6 [45] Patented July 20, i971 [73] Assignee wean Industries, Inc.

ABSTRACT: Blanking apparatus for highly accurate blanking [54] PRESS APPARATUS operations and the like having a punch holder supporting a 10 Claims, 8 Drawing Fig punch movable toward and away from a workpiece and such punch holder carrying with it, during a portion of its move- US- ment 8 ressure member exerts a trong com- 83/458 pressive or restraining force on the workpiece during the in- [5 l Int. te -val that the punch is piercing the workpiece During a per. [50] Field of Search 83/55, 375, tion f punch holder movement pressure applying member 336353354358, 637 movement therewith is arrested whereby relative movement [56] References Cited between the pressure applying member and the punch holder occurs. The present invention provides novel means whlch UNITED STATES PATENTS prevents cocking or tilting the pressure applying member dur- 464,202 l2/ I891 Seybold 83/375 ing relative movement between the latter and the punch 758,156 4/1904 Taylor 83/458 X holder.

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ROBERT SOMAN A rim Mp PATENTEUJULZOBTI A 3,593,608

SHEET 5 u? s [A SINGLE CYCLE OF OPERATION OF O S T '1 HEAD TRAVEL TOTAL TRAVEL r OF (R055 HEAD K3 J E. Ll 1 TOP OF @2055 L o TOM OF CR .s D R vEE HEAD TRAVEL B T 0 T A PUNCH TRAVEL THROUGH STOCK INVENTOR. ROBERT 50MAN A Trawler;

PRESS APPARATUS The present invention also provides a novel mechanism which, in a mechanical press, provides the particular punch holder movement, during the working portion of its cycle, required of presses employed in the critical operations herein contemplated.

BACKGROUND AND SUMMARY Blanking apparatus for highly accurate blanking operations of the type herein contemplated have heretofore been perfonned on hydraulic press devices and, while satisfactory results have been obtained by use of hydraulic presses, such pressed have been quite massive and extremely costly because of the tremendous forces involved and because of the requisite precision guiding of the relatively movable parts which clamp and pierce the workpiece. Attempts to perform similar operations on mechanical presses have been difficult to achieve for reason that not only is the precision guiding of relatively movable parts and the resistance to very heavy forces required, as with hydraulic presses, but also required is the necessity of providing, by mechanical means a relatively slow, constant punch holder movement during the workpiece-piercing portion of its operational cycle. l

The present invention effects the requisite precision guiding of certain relatively movable parts by use of a novel equalizing mechanism which renders unnecessary the use of elongated slide members for such purpose thereby eliminating much weight, size, and complexity. The present invention further provides a novel 7 mechanical arrangement whereby the required slow, constant punch holder movement during the workpiece portion of its operational cycle is translated from constant, high-speed rotary motion.

These and other advantages of the present invention will readily become apparent from a study of the following description and the appended drawings, and in these drawings:

FIG. I is a fragmentary side elevational view of apparatus embodying the present invention,

FIG. 2 is a top plan view of the apparatus seen in FIG. 1, certain parts being broken away to show the underlying structure,

FIG. 3 is a sectional view generally corresponding to the line 3-3 of FIG. I,

FIG. 4 is a fragmentary sectional view generally corresponding to the line 4-4 of FIG. 1, certain parts being shown in another position by phantom lines,

FIG. 5 is a view similar to FIG. 4 but'showing certain parts in another position,

FIG. 6 is a fragmentary view similar to FIG. 3 but showing only the drive mechanism and the latter being shown in another position, M

FIG. 7 is a view similar to FIG. 6 but showing certain drive mechanism parts in still another position, and n FIG. 8 is a graph illustrating the movement of certain parts shown in the drawings.

DETAILED DESCRIPTION With reference to FIGS. 1 and 2, there is shown blanking apparatus comprising a base 10 above which project four ten sion members or rods 11. Rods 11 are in parallel, coextensive relation and are arranged in a virtually square pattern. As will later be disclosed, a novel mechanism within base 10 effects simultaneous movement of the rods II from the position seen in FIG. I to the position seen in FIG. 5 for a purpose to appear.

Secured to threaded, upper portions of rods 11 by means of nuts 12 is a crosshead l3 herein shown of generally boxlike configuration. Crosshead l3 presently if formed of four blocks l4, l5, l6 and 17 at respective comers thereof through which extend respective rods 11. Side members l8, 19, and 21 ex tend between and are welded to the blocks 14 through .17 to form a rigid structurally integral structure therewith. Side member 18 extends between the blocks l4, 15, side member 19 extends between the blocks 15, 16, side member 20 extends between the blocks l6, l7 and :side member 21 extends between'the blocks I7, 14. Extending between the side members 18 through 21 and welded thereto is a floor member 22 supporting a depending punch 23 (FIG. 3) whose axis is parallel with that of the rods 11 and which is preferably centered therebetween.

Suspended in spaced relation beneath the crosshead 13 is a pressure applying member 24, sometimes referred to as a blankholder in conventional apparatus. Member 24 is herein shown in the form of a plate having the same configuration, in plan of course, as the crosshead. Such pressure applying member, or plate, is slidable along the rods 11 and, although not shown, any suitable bearing device may be interposed therebe tween to insure a close fit between the plate and the rods while minimizing frictional resistance to plate movement along the rods.

It will readily be apparent that despite a close sliding fit between the plate 24 and the rods 11, such plate would have little resistance to being tilted out of the plane shown, in the event it is subjected to a loading or force not centered exactly between the four rods lll. To prevent any such tilting is the function of the mechanism next to be described.

As best seen in FIGS. 1, 2 and 3, plate 24 is suspended beneath the crosshead 13 by a pair of links 25, 25 and a pair of links 26, 26. The links 25, 25 are spaced apart from each other and are disposed in opposed relation with the axis of punch 23, their lower ends being pivotally secured to respective sides of plate 24 by means of pins 27. Spaced-apart links 26 are similar to links 25 and their lower ends are similarly secured to respective other sides of the plate 24.

As best seen in FIG. 3, the upper ends of links 25 are pivoted upon eccentric extensions 28 of a torsionally rigid shaft 29 journaled in upper portions of the crosshead walls 19, 21. Keyed or otherwise secured to the shaft 29 is a gear seg ment 30 for a purpose to appear. For reasons to be seen, the shaft eccentric extensions 28 are in axial alignment with each other.

In a manner similar to the links 25, the links 26 are pivoted to eccentric extensions 31 of a shaft 32 disposed at right angles with the shaft 29 and journaled in the cross head sides 19, 21. Also similar to the previously described structure, a gear segment 33 is affixed to the shaft 32 for unitary rotation therewith.

Means are provided for resiliently retaining the plate 24 in the position (relative to the crosshead l3) seen in FIGS. 1, 2 and 3, and in the embodiment illustrated, a commercially available, fluid-actuated device 34 is mounted on the crosshead wall 20 and has a stub shaft 35 mounting a pinion 36 in mesh with the gear segment 30. The arrangement is such that when fluid pressure is suitably connected to the device 34, its stub shaft and thus the gear segment 30 and the shaft 29 are yieldably retained in the respective positions seen in FIGS. 1, 2 and 3. Stub shaft 35, however, may be rotated by the gear segment 30 by overcoming the torque exerted by the device 34.

A device 37, similar to device 34, is mounted on the crosshead wall 21 and has a stub shaft 38 mounting a pinion 39 engaged with the gear segment 33. Device 37, of course, functions in the same manner as device 34 to yieldably retain the plate 24, the gear segment 33, and the shaft 32 in the position seen in FIGS. 1, 2 and 3.

Inoperation and referring first to FIG. 3, stock S to be blanked will be disposed beneath the punch 23 and upon a lower die portion 40 which is mounted on the base 10 and which has an aperture 41 to closely receive the punch. With the stock thus positioned, the later to be described mechanism in the base 10 will simultaneously lower the rods 11 and thus the attached crosshead 13 and the pressure plate 24, until an impingement ring member 42, which is. secured to the plate 24, is pressed against the stock. Although it forms no part of the present invention, member 42 provides a ridge 43 which outlines the piece to be blanked from the stock and is adapted to embed itself in the stock as the latter is tightly pressed between the members 40, 42. As illustrated, member 42 is apertured to closely but slidably pass the punch 23.

While the lower die portion 40 is herein shown rigidly supported on the base 10, it will be understood that it may be supported on a conventional die cushion (not shown in the interest of simplicity) which provides for limited vertical movement of die portion 40 under the pressure exerted during the stock piercing operation next to be described.

FIG. 4, in phantom lines, illustrates the position of parts when the plate 24 is at its lowermost position; that is, when the ring member 42 is bottomed against the stock with the ridge 43 embedded therein. Downward movement of the crosshead 13 will continue, however, while the plate 24 remains stationary, until the position of FIG. is reached. The punch 23, of course, during such continued crosshead movement, having been pushed through the workpiece.

During relative movement between the crosshead l3 and the plate 22 as above described; that is, during movement of the crosshead from the phantom line position seen in FIG. 4 to the full line position seen in FIG. 5, the pair oflinks 26, which, it will be recalled, are attached to respective eccentric extensions 31 of the shaft 32, will rotate the shaft from the full line position seen in FIG. 4 to the full line position seen in FIG. 5. Because of the torsional rigidity of the shaft 32, both links 26 will be compelled to move in precisely the same manner thus insuring that the opposed plate sides to which such links are connected remain in the same plane. The links 25, of course, effect rotation of the shaft 29 in an identical manner as above described and since such links are connected to the other plate sides, the plate as an entirety, along with the member 42 supported thereon, will be restrained against tilting.

During rotation of shaft 32 as hereinabove described, the gear segment 33 will be rotated therewith to in turn rotate the pinion 39 of the device 37. Similarly, rotation of the shaft 29 will effect rotation of the gear segment 30 and thus rotation of the pinion 36 of the device 34. Because of the resistance of fered by the devices 34, 37 to such rotation of their pinions, the member 42 of the plate 24 will exert a proportional compressive force on the stock.

After the punch 23 has pierced the stock, the crosshead will be elevated to its starting position. During initial upward movement of the crosshead from the position seen in FIG. 5, the croshead will move independently of and in a direction away from the plate 24 until the pairs of links 25, 25 and the pairs of links 26, 26, together with respective shafts 29, 32 return to their original positions. Further upward movement of the crosshead will thereafter carry the plate 24 therewith until all parts are in the starting position seen in FIG. I.

Turning now to the previously mentioned drive mechanism and with reference to FIG. 3, the rods 11 project into the base through any suitable bearing members 50 which permit vertical rod movement with no appreciable side play. Bearing members 150, similar to members 50, are mounted within the base 10 and slidably receive the lower ends of the rods 11 to insure accurate guiding thereof. Secured to and rigidly connecting the rods 11 together within the base 10 is a frame 51 to which are pivotally secured a pair of pitmans 52 (only one of which is seen in FIG. 3) in spaced, side-by-side depending relation. The lower end of each pitman is joumaled upon respective eccentrics 53 secured to and rotatable about the axis of a shaft 54 pivotally carried by the base. Affixcd to shaft 54 between the pitmans 52 is an arm 55 to which reference will later be made.

Spaced laterally of the shaft 54 and rotatably carried by the base to is a shaft 56 mounting an eccentric 57. Journaled upon the eccentric 57 is a lever 58 having ears 59, 60. Pivotally connected to the car 59 and extending between the latter and a pivoted anchor 6l on the base is a link 62. Extending between and pivotally connecting the ear 60 and the free end of previously mentioned arm 55 is a link 63. Affixed to shaft 56 for unitary rotation therewith is a gear 64 in mesh with a drive gear 65 adapted to be driven by any suitable drive motor unit (not shown).

With the parts positioned as seen in FIG. 3, the pitmans 52 are in their uppermost positions and thus the crosshead I3 is in its uppennost position. Note that arm 55 is at this time tilted to the right and is in one of its extreme travel positions. Assuming the stock S to be pierced is properly positioned on the lower die portion 40, gear 64 will be rotated at a constant speed in the counterclockwise direction indicated to shift the arm 55 through its mid position shown in FIG. 6 to its other extreme position (tilted to the left) shown in FIG. 5. In the position of FIG. 5, the pitmans 52 have lowered the crosshead 13 to its lowermost position thus causing the punch 23 to pierce the stock. Continued rotation of the gear 64 in the direction indicated will shift the arm 55 through the mid position shown in FIG. 7 to its extreme position shown in FIG. 3. With the parts again positioned as seen in FIG. 3, rotation of gear 64 will be arrested thus completing a cycle of operation of the press.

The arrangement of the drive mechanism between the gear 64 and the pitmans 52 (which includes the eccentric 53, shaft 54, arm 55, shaft 56, eccentric 57, lever 58, anchor 61, and links 62, 63) is such that gear 64 will rotate about 429? in shifting the parts from the position of FIG. 3 to the position of FIG. 5. On the other hand, in shifting the parts from the position of FIG. 5 to the position of FIG. 3, gear 64 will rotate only about I l7%. Thus, during constant speed rotation of the gear 64, crosshead 13 will be lowered much more slowly than it is raised. Moreover, and as may be seen in FIG. 8, the drive mechanism aforesaid causes downward movement of the crosshead 13 at a relatively constant rate during the interval that the punch 23 is piercing the stock.

With reference to FIG. 8, a single cycle of press operation is shown divided horizontally into 24 equal time increments while the vertical dimension represents vertical travel of the crosshead 13 between its uppermost position of FIG. 3 and its lowermost position of FIG. 5. Crosshead movement, of course, is traced by the curved line.

With the crosshead 13 at its uppermost, starting position at the left end of FIG. 8, downward movement thereof will be accelerated until approximately mid movement has been reached. Thereafter, further movement of the slide will be decelerated until, for a substantial portion of crosshead travel prior to its reaching its lowermost position, the crosshead is moving at a slow, relatively constant speed. It is during this slow, relatively constant speed portion of crosshead travel that the punch 23 pierces the stock. After the crosshead reaches the bottom of its stroke, it will be rapidly accelerated to its uppermost position once again, crosshead movement being slowed, however, just before it reaches its uppermost position, to prevent shock.

Iclaim:

l. Blanking apparatus having a punch holder supporting a punch which is adapted to pierce a workpiece upon relative movement between such workpiece and said punch in a direction axially of the latter, and a member in encircling relation with the axis of said punch for applying pressure to the workpiece during piercing thereof and movable axially of and relative to said punch during such piercing, the improvement comprising:

two pair of members extending between and connecting said pressure applying member to said punch holder, the members of each member pair being disposed in opposed relation relative to said punch axis and said members being evenly spaced thereabout;

and means extending between the members of each member pair and preventing relative motion therebetween upon movement aforesaid of such pressure applying member to prevent tilting of the latter.

2. The construction of claim I wherein each of said memhers is movable relative to said punch upon pressure applying member movement aforesaid.

3. The construction of claim I wherein said means comprises respective rotatably mounted shafts which rotate during movement aforesaid of said pressure applying member, the torsional rigidity of each of said shafts resisting relative motion between the members of a respective member pair.

4. The construction of claim 3 wherein said shafts lie in different planes to avoid interference therebetween.

5. The construction of claim 3 wherein the torsional rigidity of each shaft is such that material relative movement between the members of a respective member pair is resisted during normal working stresses on the apparatus.

6. The construction of claim 5 wherein yieldably resists rotation of one of said shafts to yieldably resist the aforesaid pressure applying member movement 7. The construction of claim 6 wherein said yieldably resistance means comprises a fluid cylinder exposed to sufficient pressure to develop the resistance force required.

8. The construction of claim 5 wherein each member of said member pairs comprises a link having one end pivoted to said pressure applying member,

and wherein each shaft is carried by said punch holder and has spaced-apart crank portions to which the opposite ends of respective members of a member pair are pivoted.

- 9. The construction of claim 1 wherein said punch holder and the punch supported thereby are movable toward and away from the workpiece,

wherein said punch holder and said pressure applying member are unitarily movable during a portion of punch holder movement,

and wherein said punch holder is movable independently of said pressure applying member during another portion of punch holder movement.

10. The construction of claim 9 wherein said means comprises respective shafts rotatably carried by said punch holder and said shafts rotating during the aforesaid movement of said punch holder independently of said pressure applying member, the torsional rigidity of each of said shafts resisting relative motion between the members of a respective member pair.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 593 608 Dated ul) 20 1971 Robert Soman Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 21, "42 1/2" should read 242 l/Z Claim 6, first line, after "wherein" insert means Signed and sealed this 21st day of December 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents FORM PO-IOSO (10-69) USCOMM-DC 60376 P69 & U 5 GOVERNMENT PRINTING OFFICE 9G9 O-J56-J$4 

1. Blanking apparatus having a punch holder supporting a punch which is adapted to pierce a workpiece upon relative movement between such workpiece and said punch in a direction axially of the latter, and a member in encircling relation with the axis of said punch for applying pressure to the workpiece during piercing thereof and movable axially of and relative to said punch during such piercing, the improvement comprising: two pair of members extending between and connecting said pressure applying member to said punch holder, the members of each member pair being disposed in opposed relation relative to said punch axis and said members being evenly spaced thereabout; and means extending between the members of each member pair and preventing relative motion therebetween upon movement aforesaid of such pressure applying member to prevent tilting of the latter.
 2. The construction of claim 1 wherein each of said members is movable relative to said punch upon pressure applying member movement aforesaid.
 3. The construction of claim 1 wherein said means comprises respective rotatably mounted shafts which rotate during movement aforesaid of said pressure applying member, the torsional rigidity of each of said shafts resisting relative motion between the members of a respective member pair.
 4. The construction of claim 3 wherein said shafts lie in different planes to avoid interference therebetween.
 5. The construction of claim 3 wherein the torsional rigidity of each shaft is such that material relative movement between the members of a respective member pair is resisted during normal working stresses on the apparatus.
 6. The construction of claim 5 wherein yieldably resists rotation of one of said shafts to yieldably resist the aforesaid pressure applying member movement
 7. The construction of claim 6 wherein said yieldably resistance means comprises a fluid cylinder exposed to sufficient pressure to develop the resistance force required.
 8. The construction of claim 5 wherein each member of said member pairs comprises a link having one end pivoted to said pressure applying member, and wherein each shaft is carried by said punch holder and has spaced-apart crank portions to which the opposite ends of respective members of a member pair are pivoted.
 9. The construction of claim 1 wherein said punch holder and the punch supported thereby are movable toward and away from the workpiece, wherein said punch holder and said pressure applying member are unitarily movable during a portion of punch holder movement, and wherein said punch holder is movable independently of said pressure applying member during another portion of punch holder movement.
 10. The construction of claim 9 wherein said means comprises respective shafts rotatably carried by said punch holder and said shafts rotating during the aforesaid movement of said punch holder independently of said pressure applying member, the torsional rigidity of each of said shafts resisting relative motion between the members of a respective member pair. 